Popular smoking articles, such as cigarettes, have a substantially cylindrical rod-shaped structure and include a charge, roll or column of smokable material, such as shredded tobacco (e.g., in cut filler form), surrounded by a paper wrapper, thereby forming a so-called “smokable rod”, “tobacco rod” or “cigarette rod.” Normally, a cigarette has a cylindrical filter element aligned in an end-to-end relationship with the tobacco rod. Preferably, a filter element comprises plasticized cellulose acetate tow circumscribed by a paper material known as “plug wrap.” Preferably, the filter element is attached to one end of the tobacco rod using a circumscribing wrapping material known as “tipping paper.” It also has become desirable to perforate the tipping material and plug wrap, in order to provide dilution of drawn mainstream smoke with ambient air. Descriptions of cigarettes and the various components thereof are set forth in Tobacco Production, Chemistry and Technology, Davis et al. (Eds.) (1999) and U.S. Pat. No. 7,503,330 to Borschke et al, which is incorporated herein by reference. A cigarette is employed by a smoker by lighting one end thereof and burning the tobacco rod. The smoker then receives mainstream smoke into his/her mouth by drawing on the opposite end (e.g., the filter end) of the cigarette.
Certain smoking articles may be constructed as cigarettes of a type constructed with a physically separate fuel component, aerosol generator or substrate, and mouthpiece component. See, e.g., U.S. Pat. No. 4,714,082 to Banerjee et al., which is incorporated herein by reference. Apparatus and processes for mass producing such improved cigarette smoking articles are disclosed, for example, in U.S. Pat. No. 5,469,871 to Barnes et al.; U.S. Pat. No. 5,560,376 to Barnes et al.; and U.S. Pat. No. 5,727,571 to Meiring et al., each of which is incorporated herein by reference.
Certain types of cigarettes that employ carbonaceous fuel elements have been commercially marketed under the brand names “Premier” and “Eclipse” by R. J. Reynolds Tobacco Company. See, for example, those types of cigarettes described in Chemical and Biological Studies on New Cigarette Prototypes that Heat Instead of Burn Tobacco, R. J. Reynolds Tobacco Company Monograph (1988) and Inhalation Toxicology, 12:5, p. 1-58 (2000). More recently, a cigarette has been marketed in Japan by Japan Tobacco Inc. under the brand name “Steam Hot One.” It has also been suggested that the carbonaceous fuel elements of segmented types of cigarettes may incorporate ultrafine particles of metals and metal oxides. See, for example, U.S. Pat. App. Pub. No. 2005/0274390 to Banerjee et al., and 2011/0180082, each to Banerjee et al., each of which are incorporated by reference herein in its entirety.
In the manufacture of such cigarettes, the fuel component may include an extruded carbonaceous fuel element that is circumscribed by a resilient insulating jacket, such as a mat or layer of glass fibers, and is then overwrapped with a cigarette paper or paper-like material and glued, e.g., with a cold adhesive seal, along a longitudinal seam, to form a continuous cylindrical fuel rod. The continuous overwrapped fuel rod may then be cut into shorter lengths to form fuel components suitable for processing, e.g., a six-up fuel rod having a length of about 72 mm.
Yet other types of smoking articles, such as those types of smoking articles that generate flavored vapors by subjecting tobacco or processed tobaccos to heat produced from chemical or electrical heat sources are described in U.S. Pat. No. 5,285,798 to Banerjee et al.; U.S. Pat. No. 7,290,549 to Banerjee et al.; and U.S. Pat. No. 7,726,320 to Robinson et al., and U.S. Pat. App. Pub. Nos. 2007/0215167 to Crooks et al., 2011/0041861 to Crooks et al., 2012/0067360 to Conner, et al., and 2012/0042885 to Stone et al., all of which are incorporated by reference herein in their entirety. One type of smoking article that has employed electrical energy to produce heat has been commercially marketed by Philip Morris Inc. under the brand name “Accord.” Smoking articles that employ sources of heat other than tobacco cut filler to produce tobacco-flavored vapors or tobacco-flavored visible aerosols have not received widespread commercial success. However, it would be highly desirable to provide smoking articles that demonstrate the ability to provide to a smoker many of the benefits and advantages of conventional cigarette smoking, without delivering considerable quantities of incomplete combustion and pyrolysis products.
It has been found that drying of the extrudate fuel rod to a relatively low moisture content to prevent problems that may occur with a high moisture content can itself affect processing of the fuel component. For instance, if the overwrapped six-up fuel component has too low a moisture content, i.e., if it is too dry, the extruded rod may fracture or chip when the six-up fuel component is cut into individual fuel elements for assembly into cigarette smoking articles. Methods using heated forced air have been applied to address this.
It would be desirable to provide a method of and an apparatus for adjusting the moisture content of the carbonaceous fuel element to appropriate levels during assembly of the smoking articles to provide fuel components having a moisture content that is at a desired level and is not too high or too low at a given stage of processing. It would also be desirable to provide a method and apparatus for this moisture content adjustment that uses ambient air rather than requiring the extra resources and equipment needed to generate and vent/dispose of heated air flow.